Very very briefly to summarise the article - The S92 has a vibration level 42% higher than that of the Super Puma. 85db is considered to be the absolute maximum, and at this level damage can be expected. It is recommended that the level be closer to 70db for a safe working environment. The S92 is often above 85db and can be considerably higher. In all categories the S92 vibrates more and has higher noise levels than other types tested.
My point point is to the anti-helmet argument, you must take types other than your own into consideration, and the fact that there is documented evidence to support the idea that noise and vibration levels are above an acceptable threshold, mean we must do something. The aviation medical experts are of the opinion that a helmet provides the best overall protection, and that whilst ANC and other DC headsets are comfortable, as are earplugs, they do nothing to reduce the high vibration entering your skull and damaging the small mechanisms in your ear. There are a variety of solutions, of which a helmet is one. It is also the cheapest and easiest, but maybe not the most preferable to all. The alternatives require major redesign of the aircraft structure and materials used, and are not likely to be forthcoming in a short time period. I recommend for anyone interested to at least google translate the summary of the article posted.